Method of fumigating with calcium cyanide



Aug. 25, 1931. 'J. LINGLER METHOD OF FiJMIGATING WITH CALCIUM CYANIDE Fild March 9. 1929.

INVENTOR JOHANN LINGLCR ATTORNEY Patented Aug. 25, 1931 PATENT orac es UNI ED STATES Jonm'LmeLna, or orrEnBAcn-on-mnE-mum GERMANY, n'ssrenon. 'ro nnurscnn I'UERSCEAEDLINGSBEKAEMPFUNG TEE-IAIN, GERMANY, A CORPORATION MT. B. H., OF FBANKFORT-ON- METHOD Q1 F UMIGATING WITH CALCIUM CYANIDE v I imam filed March 9, 192a, s m No.

The present invention relates to the generation of prussic acid from alkaline earth cyanide compounds, for example calcium cyanide or magnesium cyanide or substances or compounds containing these, particularly for the purpose of destroying vermin.

"The destruction of vermin bymeans of, forexample, calcium cyanide "is usually ef-' fected by decomposing calcium cyanide in I) a finely divided form by the action of the moisture co tained in'the air whilst generatmg prusii c acld, for example in such a manner th t the pulverous calcium cyanide 18 gas; This method'of operation has considerable difiiculties. For the purpose of efis dispersed in the space to be treated with fecting a successful treatment with gas it is necessary to obtain as high a concentration of gas as possible within the shortest possible 20 period'of time. For example, when treating with gas trees and other lants damage to 7 the leaves must be avoide For these and other reasons the treatment with gas must always be efiected with an amount which is suited as accurately as possible to the size of the space to be treated with gas. The amount of pulverous, readily decomposed,

isonous calcium cyanide causes considerable difliculties and inconveniences particularly when treating with gas trees, which operation as is well known is as a rule effec'ted during thenig-ht. -The uantities of pulverous material to be use as stated 'above,-must'be made to suit the sizes of the spaces to be treated with gas, which latter in turn for example depend upon the size of lydetermine the trees to be treated.

As indicated above it is consequently always necessa to use different but accurate-v quantities in' order to effect with certainty the result aimed at, and to avoid burning{ of the foliage. The adjustment ofthe quantity is rendered more diflicult as the operationmust be carried out with closed measuring apparatus.

Accordingto m invention I am able to eliminate these an other difliculties in fumi- 'tion due to the use of the media in uestion m the form of powder, from a pure y technical point-of view by converting the media 845,765, and in Germany nar h 12, 1928.

which are available at the start in the form of powder first into solid form then again convertin them into the form of powder and distri uting the powder thus produced. I

into the space to be fumigated.

According to my invention I efieet this by converting the pulverous alkaline earth cyanide compounds into easily manipulated bodies which can be easily formed into doses and after forming them into doses again converting them into the pulverous condition and subsequently decomposing them in the usual manner by the action of the air or the moisture respectively contained therein.

I have found, for example, that it is possible to convert calcium cyanide and the like into shaped bodies such as slabs, briquettes and the like, which have a suflicient mechanical strength and durability and also have the great advanta e that they will readily fall, for example y simple pressure, into the form of powder. By reason of this double pro erty, which was by no means anticipate it has been rendered possible to produce shaped bodies of definite hydrocyanic acid content for example in such a manner that,v the external sha' e of the body, for example cube, ball, cylin er or the like, indicates the efi'ective hydrocyanic acid content, whereby the dosing is rendered very certain that, for example, in the dark. when the fumigation of plants, shrubs, trees or the like has to be carried through it is any suitable intermediate weights can be ob-- tained.

The conversion of the pulverous cyanide compounds into shaped bodies may'as I have found, be effected without the co-operation of binding agents. It is suflicient to press 19."

" device togfirst bring the pulverous material, according to the usual methods, by means of pressure in suitable moulds. By a suitable selection of the pressure I can influence the strength of the shaped bodies to a largeextent.

In comparison with the pulverous material used hitherto, which very readily falls to pieces and consequently can only be transported and handled in very efiiciently closed vessels, the use of shaped bodies has the further advantages thatthey have a comparatively good durability whereby their hand-- ling is considerably facilitated. The shaped bo i es through the action of air are covered by a thin superficial protecting layer which protects the contents effectively against decomposition, Artificial protecting layers may also be applied but as I have lndicated this is not necessary as a rule.

According to one method of carrying my invention into effect other auxiliary substances, for example such as are also capable of acting upon the vermin to be destroyed, as for example nicotine or suitable nicotine compounds, as for example nicotine sulphate pyrethrum derris root or stimulating or preventative substances,. which volatilize simultaneously. with the hydrocyanic acid which is given off may be incorporated with the pulverous alkaline earth cyanide compounds or the shaped bodies to be produced therefrom.

The use of the shaped bodies may for example be such that pieces having a hydrocyanic acid content correspondi with the space or the article to be treate with gas are laced into a simple device which can be easi transported and easily manipulated 'in w ich it is caused to fall into the pulverwhen using these devices are described hereinafter.

When using means for destroying vermin by fumigation in the'preferred form as indicated and mainly for the purpose of obtaining a convenient dosing the difficulty is met wlth that it is necessary before intro- 'ducing these substances into the dispersing them into a sufliciently fine form, preferab y into the form of powder, during which operation it is necessary to consider that very poisonous bodies are being dealt with so that particular care must be taken when reducing to powder, this being-particularly the case when the devices at the point of use mostly 'have to be operated by unskilled persons.

According to my invention I proceed preferably in such a manner that the comminution of the substances to be dispersed as also the production of the air stream and the dispersion by the air stream are effected by means of one and the same device, preferably by actuating one and the same operating member, for example, by hand. a As means for the production of the air stream any suitable devices of known type may be used as, for example, iston air pumps with a straight line guide 0 the member which effects the movement of the air, as also such having a rotary movement, as for example fans, rotary blowers or the like.

For the purpose of comminuting the vermin destroying media comminuting devices of the most diverse character with grinding, friction or impact action are suitable, as for example rollersrolling upon one another or discs or plates provided with grooves or recesses, which are moved past the surface of the piece to bencomminuted under pressure, or grinding devices of the type of coffee grinding machines or finally those of the character of devices based on the'impact action ofrotary parts, for example, of the type of so-called impact or perplex mills or the like. In the latter case the movement of the rotary members can be effected with advantage, if desired also while 'ving these a particular construction, simu taneously for the roduction of the necessary air stream.

The comminuting members may be arranged either in the same space in which the moving air stream is produced for example in such a manner that the comminuted material passes directly into the moving air pic, are arranged so as to be conveniently accessible from outside the' casin of the p blower, the pump -or the like, or't ey may the methods, of operation to be followed b e mounted in a separate chamber for example -leading to the actual air chamber,

which separate chamber is then preferably provided at its lower end with an outflow opening leading into the air chamber and through which the comminuted or pulverous substances, preferably under the action of gravity, pass into the air stream so that they are carried away with this. The in troduction of the powder may be effected before, at or behind the actual driving members for the air, thus both into the stream of inflowing air and into the stream of outflowing air, in the latter case provision is made, by providing nozzle arrangements of known type, in which the outflowing air exerts a suction action on the chamber containing the comminuting members or upon the comminuted material itself, for 0 50 movement of the piston.

example, in such a manner that the conveyance of the latter is-mainly due to the suction action. In all cases it is advisable to positively connect the comminuting members with the members adapted to produce the movement of the air and to the common 0 crating member in such a manner that 't e movement of all-these parts may be In the accompanying drawings are illustrated by way of example three forms of construction, which have been selected from a number of possible forms of construction,

the devices being illustrated diagrammatically whilst omitting all details such as stuffing boxes and the like. But I want it to be understood that I do not want to be limited to the devices described.

In the drawings: I

' Fig. 1 is a vertlcal section" a device, em-

body'ing my invention.

Fig. 2s a vertical form of my invention.

Fig. 3 is a side view of another modified form of my invention.

Figure 1 shows an arrangement in which section of modified the movement of the air is produced by an ordinary piston air pump and the 'comminution of the material is effected by a ribbed plate which is moved past the material in the form of a briquette in a separate chamber and is positively connected to the piston rod of the air pump. In the device according to Fi 2 the movement of the air is also produce by a pump piston which at the same time carries the'material to be comminuted, the comminution thereof being effected by means of a disc provided with grooves and positively rotated during the Figure 3 shows'in side elevation a rotary blower in which the material to be comminuted is arranged at the upper portion of the inlet opening and is "rubbed into powder by means of a grooved disc which is rotated underneath it by the shaft of the blower.

In Figure 1 a indicates the cylindrical pumpcasing provided at its lower end with an outlet opening 1' for thecompressed air,

b is the piston, w the piston and rod and 0 the handle provided at the upper end thereof, d is a longitudinal slot in the piston rod in which is guided a rod e pivotally mountvertical arm 11. the lower end of-which projects into a chamber yl separate from the ac- .tual pump chamber and in this chamber carrying a grooved plate or disc 73 pressed against the briquette Z, consisting for example of calcium cyanide, by the action of a spring on and on the movement of the piston rodw, by reason -of its positive connection with the arms 0 and It moves upwards and downwards in the opposite direction to the piston rod and thus rubs the briquette into powder, this powder then flowing out through the outlet opening gat the lower end of the chamber y into the stream of air flowing out at r. In order to press the briquette Zuniformly against the disc 2' and at the same time obtain a fluid tight closure to the outside there is, provided in the laterally disposed pipe 8, for the introduction of the briquette into the chamber y, a plate of sheet metal or the like which closes tightly against the inner walls of the pipe or is secured in a fiuid tightmanner by any other means, this plate being pressed against the briquette Z by the action of a spring 0 of. which the other end bears against the cover In t e device shown in Figure 2 u again indicates the cylindricalpump casing, provided at itslower end with the inclined bottom 2 and the air outlet 1', b the piston which in this case is driven by the tube a provided with a handle 0. On the upper surface of the piston is provided the device similar to that shown in Figure 1 for comminuting the briquette, but in this case it is arranged at right angles, the arrangement being such that the briquette passes downwardly through a hole in the piston and-there bears resiliently upon the upper surface of a round' plate 0 provided with grooves and which is connected to the lower portion of the piston in such a manner that itcan turn freel and thus efiect the comminution of the briquette Z by the rubbing action of its grooved upper surface. In order to rotate this disc positively during the upward and downward movement of the piston this disc has the cened at f and pivotally connected at g to the with which engages a pin or other pro ection in the bore of the disc '0 so that at the up and down movements of the piston the disc whilst also carrying out these movements is caused to rotate by the engagement of the projection in the spiral groove.

In Figure 3, 1 indicates the casing-of the rotary blower withthe air inlet opening 2 and the outlet opening 3, 4: being the shaft to which is keyed a toothed or friction wheel located between the bearing 7 and the suction opening 2, which drives a rotary disc, forexample through a gearing mounted in the casing 5, which plate is provided with grooves in a suitable manner and is moved past a briquette, introduced through the pipe 6 in a similar manner as in Figures 1 and 2, in such a manner that the powder which is formed directly passes into the stream of air sucked in through 2.

With devices of this character the comminuting device can for example also be arranged in the outflow pipe instead of in the inflow pipe, in which case provisionis made for a suitable intermediate gear for the driving thereof from the main shaft of the blower. In the device according to Figure 1 the method of connection of the rod h to the piston red by means of a lever-.6 may also be efi'ected by other means for transmitting the movement of the piston rod to the rod h, for example, by means of a gear operating in the same direction of movement of the desired with a transmission gear, or any other suitablepositive drive. -When using devices with rotary members provided for example with impact pins it is advisable to arrange in[front of the inlet for the material into the actual operating chamber also a simple device for. coarse comminution of.

which the drive is preferably also effected positively with the other members.

By my invention I am enabled to achieve the fumigation of trees, shrubs or the likein the shortest possible time and 'very efiica- 'ciously even in night time without incurring reducingthe shaped bodies into powder, and

blowing the said fumi ated.

2. method of fumigating which consists in converting a cyanide of a metal selected from the group comprising alkaline earth metals and magnesium, into shaped bodies of a size the hydrocyanic acid content of which corresponds to the amount required for fumigating, reducing the shaped bodies into powder, and blowing the sa1d powder into the space to be fumigated.

3. A method of fumigating which consists ,inconverting a cyanide of a metal selected from the (group comprising alkaline vearth metals an magnesium, into shaped bodies which allow of subdivision of definite size and hydrocyanic acid contents, reducing the powder into the space to be reducing same into powder by grinding,"and

from the group comprising alkaline earth metals and magnesium, into shaped bodies, reducing same into powder by means of a grinding device which also blows the powder produced into the space to be fumigated.

6. In combination,v a closed container having an abrading surface, means for yieldin 7 1y holding a sha ed solid body against sald' surface, means or causing relative movement between sa1d surface and sa1d body whereby said body is owdered, and means for blowing the pow er out of said con:

tainer.

Si ned at Frankfort A/M, Germany, this ,9th ay of October, A. D. 1929.

piston rod, for example rack mechanism, if

J OHANN LINGLER.

shaped bodies into powder, and blowing the" said powder into thespace to be fumigatedz] 4. method of fumigating which consists in converting 'a cyanide of a metal selected from the group comprising alkaline earth meta s and magnesium, into shaped bodies, 

